LAUSR

We report the case of a 50‐year‐old male with peripheral T‐cell lymphoma who underwent allogeneic hematopoietic stem cell transplantation and developed overlap chronic graft‐versus‐host disease (ocGvHD) requiring extracorporeal photopheresis (ECP). His clinical presentation included a maculopapular rash with jaundice, hepatosplenomegaly, hyperbilirubinemia, and elevated liver enzymes. Liver biopsy findings were not consistent with GvHD or lymphoma but were suggestive of drug‐induced hepatitis. ECP was initiated using the Therakos CellEx Photopheresis System. During the initial sessions, dark green plasma discoloration was observed, accompanied by multiple plasma/red blood cell interface‐related procedural alarms. These challenges were managed through various operator adjustments, and the procedures remained safe and effective. Over four ECP sessions, both the discoloration and opacity of the plasma progressively improved, in parallel with declining liver enzyme levels and a reduction in procedural alarms. This temporal association between hepatic recovery and improved interface stability during ECP has not been previously described in the context of ocGvHD. Although dark green plasma is an uncommon finding in this setting, it should prompt evaluation for underlying hepatic dysfunction and timely management of plasma/red blood cell interface issues to ensure safe and effective ECP delivery.